“外部尺寸”block元素的流动性.png
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
.width {
width: 100%;
}
.nav {
background-color: #cd0000;
}
.nav-a {
display: block;
margin: 0 10px;
padding: 9px 10px;
border-bottom: 1px solid #b70000;
border-top: 1px solid #de3636;
color: #fff;
}
.nav-a:first-child { border-top: 0; }
.nav-a + .nav-a + .nav-a { border-bottom: 0;
}
</style>
</head>
<body>
<h4>无宽度，借助流动性</h4>
<div class="nav">
<a href="" class="nav-a">导航1</a>
<a href="" class="nav-a">导航2</a>
<a href="" class="nav-a">导航3</a>
</div>
<h4>width:100%</h4>
<div class="nav">
<a href="" class="nav-a width">导航1</a>
<a href="" class="nav-a width">导航2</a>
<a href="" class="nav-a width">导航3</a>
</div>
</body>
</html>
